Riveting machine



April 6, 1948. E. F. TUTTLE RIVETING MACHINE 2 Sheets-Sheet 2 I Filed Feb. 1, 1943 fugene F iZzrr/e INVENTOR. ,BY f

ArraR/vn Patented Apr. 6, 1948 ill'iED RIVETING MACHINE Eugene F. Tuttle, North Hollywood, Calif., as-

signor to Douglas Aircraft Company, Inc.,

Santa Monica, Calif.

Application February 1, 1943, Serial No. 474,405

9 Claims. 1

This invention relates to a riveting machine and particularly to a stationary hydraulically operated riveting machine.

It is an object of the invention to provide a riveting machine inwhich by one act of the operator and in automatic sequence an initial light setting pressure is applied to bring the dies into contact with the rivet head and shank, followed by a very heavy pressure adequate to upset the shank of the rivet, and in which this sequence is effected by a simple inexpensive and reliable mechanism.

Thickness of the bucked head is the best determinant for the regulation of the riveting action. If the bucked head is too thick, it is of correspondingly smaller diameter and may be pulled into the bore of the riveted article. If the bucked head is too thin, the peripheral overlying flange portion of the head will break ofi or bend, permitting the rivet to become loose or disengaged from the riveted bodies,

Furthermore, if several rivets are to be upset at one operative cycle of the machine, obviously, thickness of the bucked heads, rather than attainment of a given degree of pressure, determines the duration of the period of effective pressure application. Otherwise the set of the machine must be changed whenever the number of rivets per pressure application is changed and care must be exercised that the work be placed forengagernent of the same number of rivets at each operation.

Multiple riveting is therefore not practicable unless the riveting operation is regulated by thickness of the squash. Multiple riveting saves time and obviates the clinching or lateral displacement of the bucked head Whichoccurs when a single rivet is bucked at an angle other than a right angle.

It is therefore another object of the invention to provide a riveting machine which will upset the rivets with a predetermined thickness of the upset material or squash overlying the riveted article, irrespective of the length of the shank projecting beyond the face of the adjacent riveted article prior to the riveting operation, and irrespective of any Variations in the riveting pressure applied to different rivets by the machine.

It is still another object of the invention to provide in a riveting machine an automatic mechanism for accomplishing the last recited object which is simply constructed, dependable and accurate in operation and may be readily adjusted to vary the thickness of squash.

It is still another object of the invention to provide manual and remote controls of a pres- 2 sure cycle correlated to the thickness of the squash, which are convenient to operate, require little attention by the operator, and which provide for emergency termination of the pressure cycle.

It is also an object of the invention to provide one such control for a riveting machine, which will, as a result of one movement of a control member, set up and complete the operative cycle and also by a movement of the same control member terminate a partially completed operative cycle to meet an emergency situation, the control after either control movement being reset for the next operative cycle,

Other objects and advantages of the invention will appear upon an understanding thereof gained from this description, the accompanying drawings and the appended claims.

In the drawings which are forillustrative purposes only,

Figure 1 is a schematic view showing the pressure fluid circuits of a machine embodying the invention.

Figure 2 is a side elevation partly in section of the work handling portion of a machine embodying the invention.

Figure 3 is a vertical sectional view of the pressure booster.

Figure 4 is an enlarged elevational View of the pressure pad and associated parts.

Figure 5 is a diagrammatic view of an alternative system for the control of the riveting heads of the machine.

Figure 6 is an elevational view of the sleeve for regulating the length of stroke of the ram.

In Figure 2 of the drawing a C frame l0 provides a work receiving throat l2 and mounts below the throat a riveting buck holder l4 pivoted to the frame at I! to swing outwardly from the throat It. The holder It carries an anvil or riveting buck it, having an upper anvil face It and being vertically slotted at H, to accommodate the tie pins Ztwhich connect the side plates 22 of a pressure pad 29 which engages the under surface of the lower one of two or more sheets of metal or other articles to be riveted together. As seen in Figure 4, a plurality of stiff springs 24 seated in bores in the buck l6 and bearing upwardly against the tie pins 2|, urge the pressure pad toward the upper limit position shown in Figure 2, in which the tie pins 2| bear against the upper ends of the slots H in the buck It. The buck holder i4 is releasably held in operative position by a manually operable slide l5 pivotally connected at one end to the buck holder l4 and fixed to the 0 frame for limited longitudinal 3 movement through the groove formed therein and the lock pull operating therein. It will be seen that movement of the slide l5 to the left, as viewed in Figure 2, will pivotally move the buck holder and the elements associated therewith from beneath the ram, while return movement of the slide will pivotally move the buckholder and its elements back into'the operative position shown in Figure 2.

A ram 26 is vertically slidably mounted on the 1 frame lil above the buck IE, carrying at its lower end a rivet set 28 which is movable downward between the plates 22 toward theanvil face I8;

The ram 26 is forceddownwardly by a-hydraulic piston 39 within a hydraulic cylinder'32 -carried by the frame It). A spring 34 retractively lifts the ram 26, when the hydraulicxpressurepinthe;

cylinder 32 is released.

The 6 frame In is suspended from a carriage it which travels horizontally in a direction perpendicular' to the sectiontplaneor Figure. 2. A heavy .spring: 45;f1disposed: (under compression. be;

tween a ring- 39 fixedly seated :in "the upperend:

of a bore 41 mthe-"C framepandf collar 35" on the lower end ot a rod- 363 dependently secured to the carriagegin-effect :counterbalances the Weight-0f the C 'frame-and does not hinder an upward =movement oft the C frame: when acte'd h v upon by an upwardly directed-force;. A

As best seen' in. Fig*ure -6:,"an insert sleeve i9 formed with a steppedaperture l I cooperates:

with a radial pin-23'onthe-ram2fi to variably limit the length of strokeof theram to corre spend with work articlesof different thicknesses. The work stroke of-the ram; should be just long enough for any given job to permit ready and convenient insertion of the'fw'ork articles between the-rivet set and-buck.= Greaterlength-involves loss of time for both machine and operatoriand.

consequently 'an increase i-n-the cost ofoperation.

Rotation-of sleeve lfi t0 bring-the pin- 23 in lowermost. position? extends? c upwardly from the duit id leadingfroma source-of:pneumaticpressure or exhaust conduit 38, witha conduit 42'. Conduit 42 connects with an inlet opening at the spring=,'pressed piston ,-57 'r'moderate's the pressure. in chamber ,52 rduring the initial stages of the top of a pressure reservoir 44 filled with oil or other suitable hydraulic pressure medium to a level 43 near the top of the reservoir. The'cham ber 52 of a secondarypressure booster cylinder at within thereservoir communicates with the 29 engage the undersurface of the lower of two work articles 55 which are-to be rivetedtogeth er, V

bringing the work articles into closepressural contact. Thereafter rivet set 28 engages the manufactured head of a rivet or rivets 53 placed in rivet holes in the 'two work articles 55. As soon as this latter engagement is effected the air pressure in the circuit rises. When it reaches a predetermined pressure, as for example 50 pounds, a piston 62 of a piston valve 6! in a borefifi in a valve casing 58 moves the pistont-valve to the left against the action of a retrieving spring E3 inresponse to air pressure acting upon the right endface of thepiston 62 through the branch conduitbfi; The valve piston 62 uncovers the end of a conduit 64 through which air then flows to the chamberoi a primary booster air cylinder -66 in which appiston fiii reciprocates, a cross connection 14- leading from conduit 64 through valve casing- 581419 an exhaust conduit is being closed at this time by piston 62.

A--plunger i0 is pushed upwardly against the retrieving action of a spring i2 by the piston 68 into..the ,chamber:;52 of the;secondarybooster cylinder llfifcutting ofi' the inlet-ports 48; The plunger is formed. with spiraled grooves; Eli

through, which oilflowsfroin port t8- into cyl= inden chamberEZ when theplungerris'in its'lowermost'position.

When ports 48am, cut off, a very high-pressure,- as forexamplebTOG-p.is. i., will be generated in chamber 52 by reasonl-cof-thevnow: higher pneu-- maticypressureinconduitsn iz -56'5-and '64 and the. pressureemultiplying-c effects of the relative; areas of piston 68 and plunger Hi. The high pres-,

sure thus brought to bear on piston aesquash'es the-shank end of rivet: 53 ato form :a squashed ram 26 are held against furtherqdownwardmove-t ment;. .The 0" frame Ill andwbuck-l6 are then moved :upwardly-by :hy-draulic action during :the

rivet'squashing'action,

Asshownin'Figurefi the plunger Ni when in its levelv of 'the'ports- 4B sufiicientlyato' have-its upper end 'aboveathe uppermost chevron of the packing v'ily. L'Ihisiarrangement protectsthechevrons from destructive: action by r-the an'nular edge: '01"- the plunger atsthe'upper endzoftheflangea. .The spiral character of the grooves 5i) 'minimizes cutz ting action on the packing achevronsaby the edges;

ofithe grooves 50;

A" buffer chamber-1i 59'? having a downwardlyupward movement of the plunger 70 to. protect the chevrons from thegdamaging effector the ap-.

.plication of the "otherwise; excessive pressure to the chevrons through ;the-?spira1 grooves '50.

Revertingto Figure'.1,'when'the valve 48' is turned,'in a manner to be presentlyexplainedrto the release position shownsin Figure 1, connect-. a

ing conduit 4 2" withrthe exhaust-conduit Its piston 52 is'moved'to the rightbythe force of spring 63 acting-against "the, exhaust pressureginfitgthe piston er shutting oft-conduit 64" from conduit 55 and the annular sport. i=5" connectingconduit "M with exhaust conduit; IBiivPistOn 1'68 is now: re

turned to its 'lowermost ipositionby the .spring 12* and: downwardrimovement:lof" the plunger 10 opens ports d8 permitting-"the spring 34 to re f tr'actthe ram 26'.

Valve 40; shown schematically: in Figure? 1i, is.

housed in "a valve structure 80 which is mounted. on a'plate 84 =hinged at 85 to the frame In astating the shank and a spring 8'! for holding the plate 84 against the knob. Manual rotation of the knob 83 varies the spacing of plate 84 from frame I0. I

The valve 40 is conveniently represented schematically in Figure 1, and comprises a slidable valve element connected to reciprocate with the plunger pin 82 shown in Figures 1 and 2 of the drawings. The valve is spring loaded to take the release position shown in schematic Figure 1. The pin 82 is shown in Figure 2 in the pressure position in which conduit 42 is connected with conduit 49 leading from the source of pneumatic pressure. When in the release position the pin 32 projects substantially further to the right than it does when in the positionshown in Figure 2.

The pin 82 is pressed inwardly against the spring loaded valve by an arm 89 of a bell crank lever 88 which is pivoted to a shaft92 carried by a bracket 93 extending outwardly from the plate 84. The lever arm 89 is pushed inwardly against the pin 82 by a pin 94 on a manual lever 90 which.

is also pivoted upon the shaft 92.

The other arm 9| of the bell crank lever 88 extends into a slotted opening 95 in the plate 84 to present a catch face 96 to engage frombeneath the tip end 91. of alatch rod 98 one end of which extends into the slotted opening 95 from the opposite direction. The latch rod 98 is slidably mounted in the frame I0 and loaded by:

the spring I00 to assume the extreme position shown in Figure 2 of the drawing as determined by contact of the upper arm of a bell cranklever H92 with the lower end of a plunger I06 having a longitudinally extending groove formed therein for receiving the one end of a stop screw I I0. The lower arm of the lever I02 pivoted at I04 to the other end of thelatch rod 98. The stop screw llolimits travel of the plunger I06 and prevents its accidental removal from the die holder I4. A pin I01 slides in a bore in the buck It in axial alignment with the plunger I06, and is held by a spring I08 to an uppermost position in which it projects into the central slot I ,I.

The plunger I06 may be depressed by downward movement of that one of the tie bars 2I of the pressure pad 20, which contacts the upper end of the pin I01, causing it to engage and move downwardly the plunger I 06. When the pressure pad is depressed a predetermined distance under the pressure of the rivet set 28 transmitted to the pressure pad through the work articles 55 and resisted by the springs 24 as shown in Figure 4, the plunger I06 withdraws the latch rod 98 just far enough to clear the catch face 96, permitting clockwise movement of the lever 88 and allowing the spring loaded valve 40 to assume the release position. At this position of the pressure pad 20, the vertical spacing between the upper edges of the flanges 22 and the bucking face I8 is the thickness of the squashed rivet heads.

A dial 99 on the periphery of the knob 83 and scaled to indicate variations in the position of the pressure plates 22 relative to the bucking plate surface I8 in thousandths of an inch indicates to the operator the correct position of the knob for any desired thickness of squash.

In operation, the handle 90 is pushed to the left to place valve 40 in pressure position, and

latch it in that position- It remains in pressure position until the rivet head or heads have reached the desired thickness, at which juncture the latch rod 98 automatically trips the bell. crank lever 88, allowingthe spring loaded valve 49 to move to the release position.

A small rod I I I is longitudinally movable in a passageway II 2 in the arm 9|, one end of the rod I l I lying close to the end 97 of the latch rod 98 andthe other end of the rod III lying close to a shoulder II3-on the handle 90. To stop the riveting operation after its initiation, and before the end thereof, as in case of emergency, the operator pulls to the right on handle 90, causing rod III to push latch rod 98 to the left against the action of spring I00 and releasing bell crank lever as which in turn allows valve 40 to assume the release position. The handle after it has been pushed to the left .is held against a rightward gravity movement with respect to the latched bell crank lever88 by engagement of the shoulder II3 with the adjacent endof rod III.

Whether valve 40 is released automatically or manually,the device is properly set thereafter for the initiation of the next riveting operational sequence. i

In the control described above, a lever is manually thrown in one direction from an inoperative position to a latched operative position. The hand is removed from the lever and the operational sequence is automatically performed without further act by the operator. At the end of the operation the manual lever is automatically returned to the initial inoperative position. For emergency control the sequence may be interrupted and terminated by throwing the lever in the opposite direction from that of its initial movement.

Figure 5 shows another control in which the operator pushesa spring retrieved lever to a posi-- tion and holds it there until the operative sequence is automatically completed, whereupon he allows the retrieving spring to return the lever to its initial position ready for the next riveting operation. In case of emergency he takes the manual pressure from the lever, allowing it to return to its. initial position before the completion of the cycle. In that case the rivet set is elevated before the completion of the application of the squashing pressure and the lever is left in position for the next riveting operation.

This control is carried out by the mechanism shown in Figure 5. A button I20, when pushed upward, causes lever I.2.I to rotate about its pivotai support at I22 and by means of latch I23 pivoted to the lever I2I at I24 to push lever I25 also pivotally mounted at I22 against the valve pin I26. Rightward movement of the valve pin E28 closes an exhaust port. I 21 leading to a conduit 38a corresponding to the conduit 38 of Figure 1, and opens valve I28 permitting air to flow from inlet I29 to outlet I30 through passages as shown and thus initiating the operational sequence of the pneumatic-hydraulic .circuit described in connection with Figures 1 and 3.

The lever I25 is held in the open valve position by a catch I40 which latches under a latch MI secured upon a trip rod I42. To effect a full operative cycle, the button I20 is pushed through an overtravel after lever I25 has moved valve pin I25, the lug I43 on latch I23 striking a stationary surface I44 and rocking the latch I28 anticlockwise to disengage the latch trigger I45 from the shoulder I46. on the lever I25, which is nov'v held v inthe open valve position by the latch Mil The..-1atch;..|Z3a1isxhfild its 11 3mm assumed position imwhich zit will i etieh a et ih lever .125, ..by. .a spring:tnressedudetentiball J mounted. on glever 1121. which :sea s in ,a left h nd notch L48; intherlatch i232; the-pressur d. u z her gh i releasing. lever 1:25 clockwise, allowing .-.valve tobemoved .to the:leftgrbynlalvelspring d 33,. Shu

ting ,off air pressure .from.-..-the.nneumaticehvdrauiicicireuit .and opening etheiexhaustl-porti L121; l

The. junctur ei.,at which the release. device :tfiB: trips the11ever-;l;261is adiustablezbyxotat o :Qi h adjusting. nut 1:65;;

Shouldxit :bedesired to, stopythe. rivetrsqueez er atany itime ibefore .completionlofthe upsetting. stroke, -;the button 362i] is .-rel.eased,wnerm itting spring. :Egtii: to turn lever .lfkl: -.antisclockwise through an are 1 anddepress zbutton, :l

causing. rod (M22170.moveerightwardly and Qd-isenagin latch ri s it .fromca ch il.40,1thus permittin valve -.i2-8;rand valve pigmlfifihto. remove pressure from the pneumaticehyd'raulic,system; At'thesame time lug Hi3 strikes stationary pin l fiziturnf' ing the latch; i;231ain;a. clockwise; direction-to th position in whichxthertrig e lei-5 :is a ainready to engage shoulder: 1-bit; and. holding -'t in that. positionby the enga ement; of detent ball 14.1

I with right hand notch .5154.-

.One preferred-embodiment of the inveniilQnris thc..machine shown .=.and described herein. The invention may he lembodiednin mlienmaehines and is therefore :nQt-to be limited to; asnartic lar; machine :butis tobe; -.gi,ven the; definition of the following claims.

I claim:

In ,a riveting machine,the-combination10f: airame; a hydraulically actuated m onqthe frame for pressing downwardly up n a. =riyet head; a stationary rhuckingeplate carried by the framerbelow the ram'for'upsetting shank of a rivet; a vertically movable-louder support for the workarticles to beriveted, said support being springheldon said :frame to an upper limitlposi tion; a control valve for sthedownw d actuation of said ram .loadedatotakethe.;;non-actuating position; a latching (device iforxholdihg the. a ai -Y in the actuating :position; and means; operable upon a downward movementofsaid sup o for a predetermined distance.fonrelcasingsaid lit-Whing device.

2; The combi nationidefined in M 3 1 '1 :in which: said latching.device comprlses. apmovahl earmseparably contacting ;the said -.va1,v.e., 1a detents orengaging said -:arm. ito iiholdzit. in a. pos ti nx in which it 'holds. said-valvein.openxposition, and a means for disengaging 'saidndetentrope i hl upon a downwardzmovement roftsarid. sflppQ it tor.

engaging said arm -t0 hold 'itzz-in ta positionn I:

fit' lio. its. initial position. As lever 'slzhls-zthus moves, 118 p ioe jection lisfiilsthereon s trikessa. :pinelfizl: on and 51512;

whiqh itzholdsasaid valved-n. open pos tion and. a

manualzlever; separably contacti said .arm. Q

moving; said Iarm ztordetenteengased position, sa d lever .and .movable) arm :being .coaxially pivot-ally mountedton the shame; and means operable by a movement ofsaid :lever. away from said arm, for disengaging said detent.

5. :Theeombination. defined in eclaim .1 and in addition thereto: .amanual.,1ever;for movinesaid valveieto the .open position. when. saidilever is movediin oneldirection.

16; The combination. defined. in claim .1 andin addition thereto: .a manual lever for moving said valve.- to the .openz-position .when said lever is moved :in .oneidi-rection .and:.-means operable :upon

movement of said. lever in .the opposite direction.

forereleasing said. latching means.

"15in a riveti-ngamachine, the combination of:

axially.- .rela-tivelyu movable members for engaging.

theshankiand' head respectively of .a rivet set in positionxin .work articles for upsetting the rivet shanlcyhydraulically operated means for app1y-. ing pressure-to said members to :upset the rivet shank; ah-worklarticlelengaging member axially;

mounted onsaid valve structure and the other of whichis mounted on said frame, the frame mounted'one of which being releasingly actuated incorrelation with movement ofsaid article engaging member relative to said shank engaging member in a direction away from said rivet head engaging mem-ber, -and the juncture of the release of said latch and catch member being dependent upon the-said-spacing of said valve structure and frame. V

.8: In a riveting; machine, the combination of: axiallyv relatively movable: members f or engaging the shank andJ-head respectively of a rivet. s etin positioninwork articlesfor upsetting the rivet shank-o-meansfor applying pressure .to said members :tokupset :therivetshank; a work article Jengaging -.=memberaxially -movable relative to .said

shank aengaging smember and =10adedto move relative to said shank :engaging memberin a .direc: tion toward the rivet head engaging member; a control devices for energizing said pressure apply: ing means in a first :position and =deeenergizing saidpressure applying means in a secondposition; means loadingsaidcontrol device in the second position; a member movable between a first and second position and sonar-ably engaging said control device -formoving said control device to the first position thereof against the action of said loading-means when said member moves to the second-position thereof; a .latchforrholding said nsiovable memberzin-its first position. and areleasable: zin responsesto :a movement of, a predetermined extent of saidgahticle enga in :membe relativeiosaidshank engaging member 11 a directienaway r rornlsaid ri et eade easine memher; and a control lever arranged by a given movement in one direction to move said movable member from released to latched position when said member is in released position and by substantially the same movement in the same direction to unlatch said member when it is in latched position.

9. In a riveting machine, the combination of: axially relatively movable members for engaging the shank and head respectively of a rivet set in position in work articles for upsetting the rivet shank; means for applying pressure to said members to upset the rivet shank; a work article engaging member axially movable relative to said shank engaging member and loaded to move relative to said shank engaging member in a direction toward the rivet head engaging member; a control device for energizing said pressure applying means in a first position and de-energizing said pressure applying means in a second position; means loading said control device in the second position; a member movable between a first and second position and separably engaging said control device for moving said control device to the first position thereof against the action of said loading means when said member moves to the second position thereof; a latch for holding said movable member in its first position and releasable in response to a movement of a. predetermined extent of said article engaging member relative to said shank-engaging member in a direction away from said rivet-head engagi 9 member; and a control lever arranged by a given movement to move said movable member from released to latched position when said mem- 10 her is in released position and by a like retrograde movement to unlatch said member when it is in latched position.

EUGENE F. TU'I'ILE.

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